1. Technical Field
Embodiments relate to a secondary battery. More particularly, embodiments relate to a secondary battery that can improve safety by controlling a short between electrode plates by using a can whose front and rear surfaces are asymmetrical to each other about a direction of a long edge and which may constantly reproduce a deformation shape when the battery is vertically compressed.
2. Description of the Related Art
A secondary battery may be manufactured by first forming an electrode assembly by winding cathode and anode plates and a separator interposed therebetween in a jelly-roll shape. Then, the electrode assembly may be disposed in a can with electrolyte. Finally, an upper opening of the can may be sealed with a cap assembly.
The can may have a roughly rectangular shape for a rectangular type secondary battery, and may be a metal container made of lightweight conductive metal, e.g., aluminum (Al) or aluminum alloy. Therefore, the can may function as a terminal in itself. The can may be formed by, e.g., deep drawing. All surfaces of the can may be formed to have the same thickness.
In a conventional secondary battery, the can may be deformed when physical impact is applied to both sides of the can about a vertical axis of the battery in a standard test, e.g., vertical compression, and accordingly the electrode assembly contained in the can may also be deformed. However, as described above, all surfaces of the can may have the same thickness; and thus it may be impossible to predict the deformation shape caused by an impact. In other words, it may be very difficult to obtain reproducibility of deformation because the can may be non-directionally deformed by, e.g., a vertical compression test or external impact. In addition, the electrode assembly in the can may also be exposed to irregular pressures. Accordingly, there is a problem that a short between electrode plates may occur at various positions to cause, e.g., fire, rupture, and/or explosion.